[aprssig] OpenTracker support for 1-wire weather

[Scott Miller]

I've just released a new firmware image for the OpenTracker that will
support the base model of the Dallas/AAG 1-wire weather station (v3 only.)
It's available for download at http://n1vg.net/opentracker.  As usual, the
firmware can be downloaded directly from the config program, but you'll need
the new config program to set the weather-specific settings.  It's still in
beta, so use at your own risk.

Setup is pretty simple - you need to set your coordinates, beacon rate,
path, power control settings, status text, and status text interval.  It'll
send a standard, complete APRS weather packet containing position, wind
direction, wind speed, gust speed, and temperature.  Every 1 to 255
transmissions, if enabled, it'll send a text status message, plus battery
voltage and board temperature.

The only thing that needs to be calibrated is the wind vane.  Set the vane
up, point it in a known direction, and set the offset until it reports the
direction correctly.

For hookup, just connect the station to +5 volts (parasitic power mode
hasn't been tested yet), ground, and data (pin JP8 on the OpenTracker.)
You'll need a pull-up resistor (1k seems to work) from the data line to +5
volts.  Works fine with 20 feet of satin telephone wire.

I've had a station running in the back yard all week.  I disconnected the
solar panel a few days ago, and the 7.5 AH battery is still reporting 12.3
volts.  It's driving an Alinco DJ-F1T at 100 mW every 20 seconds to 5
minutes, depending on whether I'm working on it or not.  I'm heading off to
the local soaring association meeting in a bit, and we'll probably do our
first test installation at the paraglider training hill soon.

Barometer and rain gauge support will follow, probably after DCC.  Hasn't
been a big priority for me, seeing as rain is something like a biannual
occurrence around here.

Scott
N1VG